If anyone can assume the Hollywood multitasking mantle worn by George Clooney, it's the puffysneaker, baggy cargo shorts, and weathered Celtics shirt–attired Mark Wahlberg, seated across the table from me in the Polo Lounge in Beverly Hills. He is an Academy Award–nominated actor who is at once vulnerably hunky (appealing to women!) and slow-burning, with an intensity bordering on rage (appealing to women and their boyfriends!). He is an Emmy-nominated executive producer of both the frothy Entourage and the thinky In Treatment. He is a deft on-set prankster: "He has an entire group of people who can somehow go out at two in the morning and, say, find a box of white mice to put in your trailer," says Elizabeth Banks, his costar in 2006's Invincible. Lastly, he is a guy who still appreciates the absurdity of his life as a movie star—the notion that he might get paid $10 million to play make-believe.

"I've heard Mark say that if you think you're more important than the last truck driver who leaves the set, you're in trouble," says John Moore, who directed him in this month's Max Payne, in which he plays a maverick cop out to get even for the murder of his family. This is not the first time one of his characters will be kicking ass on someone else's behalf. In Four Brothers, in Shooter, in The Departed, he plays a man who is always on the right side of your heart and sense of justice, if not, technically, always on the right side of the law. Don't make too much of the recurring theme, though. "I don't know if I'm drawn to playing an avenger, because you could say that I'm also drawn to playing people
who've had horrible things happen to them," the 37-year-old actor says. Sure enough, next year he'll appear as Jack Salmon, the bereaved father of a raped and murdered 14-year-old girl, in The Lovely Bones. "I was glad when I finished that one," he adds. "Anything like that is extremely upsetting, and it's different when you have kids." The habit he has of checking in on five-year-old Ella and two-year-old Michael—his children with his fiancée, the model Rhea Durham—multiple times before he goes to bed derives more from his roots than from the roles he has played. "I make sure everything's locked and the alarm is on and everyone is snug and safe because I've always been like that. I grew up in a bad neighborhood, and you have to do that."

Back in Dorchester, a working-class section of Boston, Wahlberg was probably
considered part of the bad neighborhood. Before he was a rapper or a rapper-turnedactor, he spent some time in both the "Plimthhousakrection" (that's Plymouth County House of Correction) and Deer Island penitentiary. He says he's drawn to any movie or show about prison, "even though it will give me a bad dream." But those experiences also propelled him. "I was in for just a couple months, just enough to realize I wanted more out of my life."

"Mark is so open about his past," says Banks, his love interest in Invincible, the
story of Philadelphia Eagle Vince Papale, who famously walked on the team. "When I first met him, I told him that my mom is from Winthrop [a town near Boston] and he was like, `I think I was in jail in Winthrop once.' He's so grateful for what he's accomplished, and he sticks with what he knows best, the same people, and his mom."

These days, those folks can hang with him at a house in Beverly Hills—one with its own putting green and a big empty room that, until his and Durham's new baby arrives in six weeks and it becomes the nursery, serves as a soccer field for Ella, Michael, and him. There's a house out back that he built for his mom, which she lived in for a year before deciding to move back to Boston. Not that he blames her. He doesn't picture his family in Beverly Hills forever; more to the point, "Rhea gives this about five more years."

How he went from juvenile offender to Oscar-nominated actor, he explains like this: "I kind of slipped through the back door." That would be a reference to his music phase, and if, in the past, being reminded of Marky Mark rankled him, he's come to terms with his old persona, though "for a while I really tried to distance myself, because I was trying to change the perception of me and do the next to impossible, which is to become a serious actor."

More than a decade after surprising essentially everyone with his tender, heartbreaking portrayal of Dirk Diggler in Boogie Nights, he says, "I don't have the pedigree that a lot of people have. I can't afford to just show up." Even when he was working on The Departed, directed by Martin Scorsese, in a role seemingly custom-made for him—based in Boston, tapping an accent that he had worked mightily to get rid of years ago—and for which he would get his Oscar nod, he couldn't fully appreciate how far he'd come. "Having my trailer on Dorchester Avenue, right by the corner that I used to hang out on—that was pretty surreal," is as much as he will allow. "But other than that, I just had my game face on. It's not that I'm stressed out [on set]. But I am engaged."

"His vigilance up to his last shot on a movie is fantastic," e-mails David O. Russell, Wahlberg's director on 1999's Three Kings and again on 2004's I Heart Huckabees. "He's not jaded or self-conscious or hung up—this is very fortunate for directors. He takes it upon himself to research everything he can about a character he's playing, and on his own will go to the place that character is from (Detroit in Three Kings, strip-mall Jersey in Huckabees) to pick up whatever he can. I don't think he will ever stop this vigilance, because it is how he approaches whatever he does, whether it's golf or his family or acting. He takes full responsibility."

For the past two years, he has been boxing in preparation for The Fighter, in which he will play "Irish" Mickey Ward, a fighter from Lowell, Massachusetts. This is the third time he has trained to play a boxer, and the first two movies fell through, so he talks about it with a wary optimism. Even so, he wakes up at five most mornings to eat breakfast and then go work out in the home gym with his friend Brian. (His arms are covered with scrapes from the Velcro on Brian's gloves.) "By eight-thirty, I come back up and I'm eating chicken, and my kids look at me like I'm crazy, like, why am I eating lunch when they're eating breakfast?"

It's entirely possible that getting his body into a specific kind of shape is just the very controllable first step to hyper-preparing and fully occupying a role. "You get out what you put in," he says. "And I want to be proud of what I do. I don't want to be embarrassed or ashamed."

In Four Brothers, he had to skate in two scenes: first in a ragtag pickup hockey game, then in a semipro hockey fight, shot from the waist up. "So of course I obsessed about that and started skating five times a week for six months." When he talks about his body, he sounds almost like a woman who has been watching her weight since the day she hit puberty; his filmography could be written with the needle of a bathroom scale. Due to the ongoing training for The Fighter, "I was able to be fit during the course of The Happening and Max Payne and The Lovely Bones," he says. "I was thin for all of it. And I feel better when I do it." For lunch he orders the Polo Lounge's signature McCarthy salad, with turkey bacon and no cheese. When the waiter arrives to toss it, Wahlberg almost apologizes for asking for it to be lightly dressed.

If you think back, Wahlberg's body was his original calling card—he was first see shirtless and jacking iron in the video for his platinum single, "Good Vibrations." This led to him becoming a Calvin Klein underwear model, dominating Times Square on a billboard that displayed him magnificently in his skivvies. This led to him acquiring the habit of dropping trou at the slightest provocation. "I have a lot of explaining to do to my kids," he says, smiling and wagging his chin. "When I was in my trailer on the set of Max Payne, my assistant had the remote and there was a clip on VH1 for Sexy People of the '90s, and he was like, `That was you.' I tried to play it like, `Yeah, someone told me about it and it was already on, so, um, change the channel.' "

But a couple of Wahlberg's friends converged on the trailer, so the channel did not budge from The 40 Hottest Hotties of the '90s (he should be forgiven for misremembering that title), "and hours later...there I was. Me talking, me running around with no drawers. All of it wrapped into one Sexy People of the '90s!" he says. (He got the number-one ranking.) "I could not have been more embarrassed. All I thought about was my kids seeing it. Because, as we all know, kids can be cruel."

There's a reason that the moment—being good-naturedly humiliated by his assistant and friends—sounds like a scene from Entourage, the hit HBO series that Wahlberg executive-produces: The show is loosely based on his own experiences and friends. Now, though, the show is in its fifth season (with five Emmy nominations and wins), and Wahlberg says he is loath to liken himself to the loose-limbed, stoner-star alter ego, because "Vince is in such a downward spiral right now.... But the friendships are real. There is a real E. There is a real Ari. There is a real Johnny Drama." His name is Johnny Alves, and everyone calls him Drama except Wahlberg, who calls him Cousin.

We have Drama to thank for Wahlberg becoming an actor. When his album Music for the People was released, he was already on probation and parole, and, he says, "I got into more trouble." His brother (and New Kid on the Block) Donnie hired Alves expressly to keep the baby of the Wahlberg family from messing up again. It's not simply that the two young men bonded. "God brought us together," Wahlberg insists.

To prove it, he recalls the first time he went back to Boston with Alves, and then to Alves' family home in Plymouth. "I see his mother and I go, `Oh, shit, Cousin, I know your mother.' And he's like, `Fuck you.' He thinks I'm joking, right? So I say, `Does she work in the jail?' " Alves' mother, it turned out, was a volunteer at the Plymouth House of Correction. "She used to come and pray with me, because I was the youngest kid in there. I'm telling you, she's an angel."

Again and again, Wahlberg makes such devotional statements. Several times, by
way of explaining a decision he made, he says, "I'm a spiritual person." But he doesn't mean it in that dippy California way. He means he is a religious person, a devout Catholic. A big rosary bead tattoo runs around his neck and down his chest (trump that, kaballah braceleteers). He goes to Mass, has visited the Vatican, and is still in touch with Father Flavin, who was his parish priest growing up. Whenever he passes a church or a crucifix, he blesses himself—he runs through "FatherSonHolySpirit amen" so quickly, it sounds like push-button speed-dial—which is why he likes Philadelphia, where he's shot four movies, so much: "Whether you're driving in or out of the city, churches and crosses are every everywhere." There's an area in his house between the living room and his bedroom where he hangs a cross and likes to pray, and tries to get his kids in the habit of blessing themselves whenever they pass.

When he marries Durham next year, it will be a Catholic wedding. She was recently baptized and confirmed, but when it's suggested that he was part of her motivation, he bemusedly insists, "Oh, no, no, no, no. She did it for her. " And yes, on the surface, there is a puzzling contradiction in such a devout Catholic waiting to marry the woman who has borne him three children out of wedlock. But his parents divorced, as did Durham's, and he doesn't take marriage lightly. When he was at the Vatican last summer, the young priest he was with explained that marriage is "equivalent to the love that God has for you; you're supposed to have that for your spouse," Wahlberg says. Which is as hard as it sounds.

He is the opposite of the celebrity who swears left and right that his relationship is rock-solid—up to the minute the publicist announces the split. "We broke up after Ella was born. We'd been on again, off again for those few years," he says. "But we always wanted to make it work, we wanted to be together, we wanted to raise our family together. And it's been a lot of hard work and counseling, and I think that's the only way to make it work, to put in the time and effort. I can't talk about why and what happened [when I left], obviously. But going away doesn't make it work." Of Durham he says, "She is an amazing woman and she's from a beautiful family." She gave him a good piece of advice for this interview. Because he tends to be soft-spoken at best and mumbly at worst, he was to lean into the tape recorder's microphone to make himself heard. "She said, `Make sure you talk about how much you love me, baby.' "

When they do get married, probably next summer, their most eager guest surely will be Ella. "She's excited, and she asks a lot of questions. A lot of questions," he says. "She's extremely smart—really articulate and tuned in to everything that's going on around her. And she's obsessed right now with princesses and fairy tales and being kissed by the prince and happily ever after and, of course, Will you marry me?" Then he offers the last of his daughter's ideas of a fairy-tale ending: "And we're all going to have the same last name."